Manufacture and use of textile threads containing cellulose acetate



Patented Aug. 10, 1937 UNITED STATES.

PATENT. OFFICE MANUFACTURE AND USE OF TEXTILE THREADS CONTAININGCEILULOSE ACE- TATE Oamille Dreyfus, New York, N. Y., and WilliamWhitehead, Cumberland, Md., assignors to Celanese Corporation ofAmerica, a corporation of Delaware No Drawing. Application May 18, 1935,Serial No. 22,175

11 Claims.

cellulose which have a high degree of creping power suitable for theproduction of crepe fabrics. A further object of this invention is thetreatment of yarns and the twisting of same to a high degree of twist insuch a manner that fabrics having a uniform creping property areproduced. Other objects of the invention will appear from the followingdetailed description.

The term organic derivatives of cellulose as used in this application isintended to include the organic esters of cellulose such as celluloseformate, cellulose propionate, cellulose butyrate and other organicesters of cellulose and also ethers of cellulose such as methylcellulose, ethyl cellulose and benzyl cellulose. Although the inventionhereinafter will be specifically described in particular connection withcellulose acetate, it is applicable for use with yarns or threads madeof other organic derivatives of cellulose such as have been hereinbeforementioned.

It has been found that if yarns of cellulose acetate are tightlytwisted, especially in the presence of steam, the same may be woven intoa fabric which produces a substantial amount of crepe. By this priorprocess, however, the amount and type of crepe produced are dependentupon a number of conditions, difiicult to regulate, that efiect thesetting of twist, the compactness of the yarn, etc. These varyingconditions which influence the type and amount of crepe that the threadswill produce cause difliculties in the manufacture of crepe fabricsconsisting entirely or substantially of threads of cellulose acetate. Byemploying this invention, however, many conditions may be disregardedwithin wide limits and threads that will produce a uniform type of crepeare formed. Furthermore, by employing this invention, the degree andtype of crepe produced is governed by fewer -variables, which may beeasily controlled, such as theamount of twist imparted to the thread,the type and temperature of treatment given to the fabric in the crepingbath and such other manual operations.

By prior methods of forming crepe fabric from threads containingcellulose acetate, it was usually necessary to subject the fabric tolengthy treatments or treatments in rope form in heated aqueous soapbaths to ca'use the threads to shrink and buckle the fabric into thecrepe pebble. Unless care was exercised, these treatments were apt toresult in permanent boil-01f creases being formed in the fabric. Byemploying this invention, however, the buckling of the fabric occurssubstantially immediately with the immersion of the same in the heatedcreping bath. The speed with which the fabric crepes allows forcontinuous creping treatments and for the fabric to be treated in openwidth and for very short periods of time, thus greatly reducing thepossibility of boil-oil creases. A further advantage of this inventionis that the fabric is creped by very short treatments with water nearthe boil. For this reason, it is not necessary to subject the fabric tolong periods of treatment in heated baths where the filaments, due totheir thermoplastic properties may be softened. The possibility of thestretching of the fabric in localized areas is thereby greatly reduced.

A still further advantage of this invention is that the threads producedin accordance therewith may contain a smaller number of turns per inchof twist than was heretofore necessary to produce a fabric ofsubstantially the same pebble or crepe properties.

In accordance with the present invention highly twisted crepe threadscontaining filaments of cellulose acetate or other organic derivativesof cellulose are produced from threads or filaments of cellulose acetateor other organic derivatives of cellulose which have incorporatedtherein a plasticizer, swelling agent or softening agent, etc., by crepetwisting in a single stage and, during the insertion of the crepe twist.steaming the threads. It is of some advantage to have moisture presentduring the steaming. Thus, during the twisting operation wet steam maybe applied to the travelling yarn over at least a portion of that partof its track in which twisting takes place.

By incorporating a plasticizer with the filaments of cellulose acetateit has been found possible to produce crepe threads which yield fabricsexhibiting crepe efiects of an excellence hitherto unattained withcellulose acetate crepe threads. Moreover, with this new .process theremay be produced cellulose acetate crepe threads which have an averagestrength very much greater than that of cellulose acetate crepe threadsproduced by a simple twisting operation without the aid of plasticizersbeing present during the steam treatment and twisting. Further, apartfrom the great advantage of a strong resultant thread, the twistingoperation itself is greatly facilitated in that twisting may besatisfactorily accomplished under conditions of twist and spindle speedwhich, in the absence of the plasticizer, would give rise to frequentthread breakage and render impossible the insertion of the desired twistor at least lead to a very weak and useless thread.

Prior to the twisting operation, which imparts the high degree or crepetwist thereto, any suitable plasticizer (i. e. solvent, softening orswelling agent, etc.) may be incorporated with the yarns or filaments.The plasticizer may be incorporated in the yarns in amounts up to 10% ormore on the weight of the yarns by adding the same to the spinningsolution or dope from which the filaments constituting the thread oryarn are formed. However, similar amounts of plasticizer may be added tothe formed yarn as a coating. Thus, up to 10% or more of a plasticizermay be added to a solution of cellulose acetate in a volatile solventand the same extruded through orifices of suitable shape and diameter toform the type of yarn desired. Either the wet or dry method of spinningmay be employed. By another modification the plasticizer may beincorporated with the yarn by applying the same as a coating to the yarnafter the yarn has been formed. The plasticizer may be applied to theyarn as the sole constituent of. the coating or along with a suitablelubricant and/or thinner and may be applied at the metier as the yarnsare formed or during any subsequent winding operation prior to impartingtwist thereto. The coating material may consist of from 5 to 100 partsof a. plasticizer and 95 to no parts of lubricating material. Thelubricating material containing the plasticizer may be applied to theyarn while the yarn is travelling as at its formation, or during anywinding operation, by causing the yarn to contact with a wick or rollerthat dips into a mixture or solution containing same or by any otherfurnishing device.

Any suitable plasticizer may be employed and by that term is meant thehigh boiling solvents, swelling agents or softening agents, etc. forcellulose acetate, as for example: the aryl sulphonamides such as paraethyl toluol suiphonamide, the alkyl phthalates such as dimethylphthalate, the di-alkyl tartrates such as di-butyl tartrate, the alkoxyesters of polybasic organic acids such as diethoxy ethyl phthalate, thepolybasic organic acid esters of the monoalkyl ethers of polyhydricalcohols such as diethylene glycol ethyl ether ester of phthalic acid,the alkyl esters of phosphoric acid such as tri-etlrvlglycol phosphate,the aryl esters of phosphoric acid such as tri-cresyl phosphate and themixed alkyl and aryl phosphates such as ethylglycol di-cresyl phosphate.Mixtures of two or more of. the above may be employed.

The yarns to be formed into crepe threads may consist of substantiallycontinuous filaments of cellulose acetate or they may containdiscontinuous filaments of cellulose acetate, the length of which mayvary within wide limits. Where discontinuous filaments are employed,they may be formed into yarns by the cotton, wool or silk method ofspinning or by breaking continuous lengths in-the yarn. For example, thethreads may be those spun from a mass of discontinuous filaments orthose prepared in the manner described in co-pending U. S. applicationS. No.

726,264, filed May 18, 1934. The yarns may be formed wholly of filamentsor fibers of cellulose acetate or the yarns may also contain filamentsand/or fibers of other materials, for instance, wool, cotton, silk,other organic derivatives of cellulose, regenerated cellulose, etc. Ifother fibers or filaments are employed with the filaments or fibers ofcellulose acetate, they may be incorporated with the yarns by formingthe yarns by a wool, cotton or silk method of spinning, or by doubling ayarn from two or more yarns, one of which contains cellulose acetate.

If desired, the filaments of the yarns to be formed into the crepethreads may contain water-insoluble compounds, such as compounds ofpigment-like character, in such form as materially to modify the lustreof the filaments (e. g. barium sulphate or titanium dioxide), or loadingmetal compounds, for example. tin compounds.

In carrying out the new process, twisting may be efiected on a device ofthe kind in which the thread is drawn ofi over the end of a rotatingpackage through a guide fixed preferably substantially in' line with theaxis of rotation of the package and is thereafter wound on a bobbin orthe like, the thread being passed, on its way from the guide to thebobbin, through steam. In this way the thread is subjected to the actionof the steam during the actual application of a substantial amount ofthe twist, or to the action of both steam and moisture if it is passedthrough steam under such conditions that moisture is present. On theother hand, any other suitable crepe twisting device may be employed inconjunction with steaming. For example, a ring twister may be used forthe crepe twisting of thread consisting of discontinuous celluloseacetate filaments. Also as an example of an eflicient type of crepetwisting device reference may be had to U. S. application S. No. 19,052,filed April 30, 1935. It is preferable that the twisting mechanism, thethread guides, the supply package, the take-up package and the steamingdevice he so arranged that the twist resulting from the rotation of thepackage or twistin mechanism is at least partly inserted while thethread is under the influence of steam.

Steaming may conveniently be effected by allowing the thread to passthrough a suitable chamber supplied with steam preferably under suchconditions that moisture is present. The chamber may be provided withsmall holes, top and bottom, to permit of. passage of the thread, andalso with a steam inlet. The size of the chamber may be suflicient toafford the thread the requisite length of travel in the steam.Alternatively, a chamber having a smaller diameter may be used, in whichcase the chamber may be provided with hollow nipples communicatingtherewith and through which the yarn passes, the nipples being ofsuflicient size to provide, together with the size of the'chamber, therequisite length of travel in the steam.

The presence of the desired moisture may be assured by supplying wetsteam to the steaming device and/or by arranging for the condensation ofsteam to supply the requisite moisture. Wet steam may be convenientlyproduced by passing steam through water at suitable velocity, forinstance, small traps for condensed water may be provided at suitableintervals in the steaming chamber and steam injected therethrough bymeans of small pipes or orifices. Another method of ensuring thepresence of moisture is to wet the thread with water. For example, thebobbins of thread may be wetted before the twisting operation or,better, water may be applied to the thread by means of a wick or otherdevice after the thread leaves the spindle and prior to its entering thesteaming device.

Steam at slightly above atmospheric pressure, or at apressure of 1 ormore millimeters of water is most conveniently employed. If desired,however, the steaming may be effected with steam at any desiredsuper-atmospheric pressures, e. g., steam at 10-25 lbs. per square inch.

A steaming treatment of relatively short duration, such as may besecured by passing the yarn at a speed of from 2 to 10 metres per minutethrough say from 1" to 3" of steam, has been found to 'give satisfactoryresults. Lengthier treatments may, however, be employed, for example,the yarn may be passed at the said speeds through 6 to 12" or more ofsteam.

The cellulose acetate filaments of the threads when the threads haveincorporated therewith a plasticizer or softener very readily undergostretching when the threads are twisted under the influence of the steamand. moisture. The amount of stretch may be measured by comparing theoriginal thread denier with the final thread denier (after untwisting).It has been found that when a cellulose acetate thread is crepe twistedby the new process involving treatment with a plasticizer and steamingduring twisting so as to produce a crepe thread of good strength andcreping properties, the denier of the resultant thread is, in general,owing to imparted stretch, less and even substantially less than if thethread is simply crepe twisted without such treatments. The stretchimparted to the filaments of the thread during the twisting operationmay, for example, be of the order of -25% of their original length, andparticularly -20%. The degree of stretching of the filaments of thethread may be such that the final denier of the crepe twisted thread isnot much in excess of or is even the same or less than the denier of thethread prior to twisting. For example, the stretch may be such that thedenier of the crepe twisted thread is from 95. to 115%, 120% or 125%, ormore, particularly 100 to 110% of that of the thread before crepetwisting, especially in case of threads having an original denier of 200or less. In the case of heavier threads, i. e., those having a denierabove 200, the denier increase may be greater and still good crepeeffects attained.

The degree of twist applied in accordance with the new process may varywithin wide limits but is, in general, less than that formerly requiredto produce the same type of crepe in the fabric. The process, moreover,permits of the insertion of twists which are impossible of attainmentwithout the steaming in the presence of a plasticizer, owing to thebreakage of the thread. This is important since it enables crepe fabricshaving very pronounced yet uniform crepe effects to be produced. Thecrepe figure can be regulated according to requirements. The degree oftwist desirable in any particular case depends upon a number of factors,including the precise effects required, and the denier and number offilaments in the thread. For example, threads of 150 denier may betwisted to about 55 to 75 or more turns perinch, while 100 denierthreads may be twisted to about 60 to 100 or more turns per inch.Proportionate twists may be used in case of threads of other deniers.

By the new process highly twisted cellulose acetate crepe threads may beproduced in which the filaments are extremely closely packed. For

ments, however, are not stuck together nor ad-- hered to each other andthey can be separated upon untwis'ting into individual filaments. Thethreads produced in accordance with the present invention have aspecific gravity of at least 85% of that of a solid thread.

The highly twisted crepe threads may be incorporated in the fabrics invarious ways, for example, the weft alone may be wholly or partiallycomposed of such threads or the warp may also contain them. Valuablefabrics may be pro duced by employing in the warp, threads of relativelylow twist and in the weft both crepe threads having a left-hand twistand crepe threads having a right-hand twist, pairs of threads ofleft-hand twist alternating with pairs of threads of right-hand twist.

If desired, the cellulose acetate crepe threads may be associated in thefabrics with highly twisted crepe threads of other materials, e. g., ofnatural silk or regenerated cellulose, or threads of artificial silkproduced by other processes.

Where the fabrics contain threads of low twist, these may wholly be ofcellulose acetate or wholly or in part of other materials, e. g.,natural silk or regenerated cellulose.

After the yarns or threads have been formed into a fabric, if saidthreads or any of said threads have been treated with very active andlarge amounts of plasticizers such as di-ethylene glycol, etc., thefabric, to produce the best creping effect, should be scoured in waterbelow 95 C. or dry cleaned to remove a part or all of the plasticizerpresent. If a large amount of very active plasticizer is present in thethread during the creping, the creping forces release themselves withoutbuckling the yarn. When the fabric is first scoured cold or dry cleanedwith an organic solvent for the plasticizer, however, it crepes heavilyand produces a very uniform fabric in the subsequent heated crepingbath. When smaller amounts or less active plasticizers are employed,such as tricresyl and triphenyl phosphate, etc., the fabric need not bescoured cold prior to the treatment in the hot bath to produce the crepeeffect on the fabric. The action of the various plasticizers employedmay be tested to ascertain which, if any, and to what extent the sameshould be scoured from the fabric in the cold before placing the fabricin the heated bath to develop the crepe effect and to buckle the threadsin the fabric. Fabrics containing highly twisted crepe threads preparedin' accordance with this invention may be scoured in the cold bath toremove a part or all of the plasticizer employed for the twistingoperation, if the same is necessary, and then subsequently be scoured,for example, in the manner adopted in connection with fabrics comprisinghighly twisted yarn be considerably lower.

of natural silk. Enhanced crepe efiects may be obtained by employingscouring or other aqueous crepe baths at or near the boiling point. Thefabric made in accordance with this invention may be caused to crepe byimmersing'the same in a bath, containing upto 10 grams or more per litreof .soap, that is maintained at about to C. However, by employingcertain plasticizers, the temperature of the creping bath may The periodof treatment in the heated bath may be from a fraction of a minute,where yarns contain a plasticizer, to 5 or 30 or more minutes where theplasticizer has been removed or is present as a coating on the yarn. Thedelustering efiect of all high temperature scouring baths upon fabricscontaining threads of lustrous cellulose acetate may be minimized byincorporating therein salts or sugars.

An important characteristic of fabrics exhibiting crepe-efiects producedin accordance with this invention is that unlike crepe fabricsheretofore produced, they do not shrink substantially when washed orotherwise treated with aqueous liquids, nor do they tend to developspots when subjected locally (such as by rain) to aqueous liquids.Therefore, garments or other articles made of such fabric may belaundered in the ordinary way without recourse to dry cleaning.

As illustrations in describing this invention and not as limitations,the following examples are given:

Example I A spinning solution is formed by mixing substantially 25 partsof acetone-soluble cellulose acetate, 75 parts of acetone and 0.5 partof diethylene glycol. This solution is spun into filaments by the drymethod of spinning. The yarn as formed is lubricated with olive oil, orother yarn lubricant, and subsequently twisted to a crepe thread byimparting thereto, in the presence of steam, a twist of about 70 turnsper inch. This yarn is woven into a fabric and then washed in waterbelow 45 C. in the presence of a. soap solution sufficient to removesubstantially 75% of the di-ethylene glycol present in the yarn. The

fabric is then treated for 10 minutes in an aqueous bath maintained at99 C. The fabric produced has a heavy and uniform crepe effect producedthereon, which crepe efiect is spot-proof and substantially free fromfurther shrinkage upon treatments in aqueous or other cleaning bathsnormally met with in the use of the fabric.

Example II A spinning solution is formed by mixing substantially 25parts of acetone-soluble cellulose acetate, 75 parts of acetone and. 1.5parts of tricresyl phosphate. This solutioh is spun by the dry method ofspinning into a yarn, which yarn is lubricated with a suitable yarnlubricant. The yarn so produced is twisted, in the presence of steam, toa crepe thread having approximately '70 turns per inch. This thread iswoven into a fabric and same immersed in an aqueous bath maintained at atemperature of above 80 C. for about 1 minute. The fabric produced has aheavy crepe effect, is exceptionally uniform and strong. This materialis spot-proof and does not materially shrink .upon further treatment incleansing baths or solutions.

Example III A yarn of cellulose acetate is caused to contact with afurnishing device which applies thereto aoeaise a coating of tricresylphosphate. The amount of coating applied to the yarn may be any suitableamount, for example, from 1 to 5%'or more based on the weight of theyarn. This yarn is twisted to a crepe thread in the presence of steam,such that approximately 70 turns per inch are inserted therein. Thethreads are woven into a fabric and the fabric treated in a hot bathmaintained at above 80 C. for a period of from 10 to 20 minutes. Thefabric produced is similar in all respects to that produced by ExampleII. In place of a coating of tricresyl phosphate the yarn may be coatedwith 2% or 3% on the weight of the yarn of a 50-50 mixture of dibutyltartrate and olive or castor oil. This yarn need not be scoured in coldwater prior to creping,

In the above specification and in the appendant claims the termplasticizer is intended to include within its scope any reagent asexplained above which has a swelling, softening or slight solvent actionupon the filaments containing cellulose acetate or other organicderivatives of cellulose at above room temperature. This term isintended to include plasticizers, softeners and swelling agents.

It is to be understood that the foregoing detailed description is merelygiven by way of illustration and many alterations may be made thereinwithout departing from the spirit of our invention.

Having described our invention, what we desire to secure by LettersPatent is:

1. Process for the production of highly twisted crepe thread offilaments containing an organic derivative of cellulose, which comprisesincorporating a plasticizer with the thread, steaming the thread andcrepe twisting the thread while it is subjected to the action of thesteam.

2. Process for the production of highly twisted crepe thread offilaments containing an organic derivative of cellulose, which comprisesincorporating a plasticizer with the thread, crepe twisting the threadof filaments in a single stage and steaming the thread during the actualinsertion of the crepe twist.

3. Process for the production of highly twisted crepe thread containingfilaments of an organic derivative of cellulose, which comprisesincorporating a plasticizer with the thread containing filaments of anorganic derivative of cellulose, crepe twisting said thread and, duringthe actual insertion of the crepe twist, steaming the thread under suchconditions that moisture is present.

4. Process for the production of highly twisted crepe thread offilaments containing cellulose acetate which comprises incorporating aplasticizer with the thread, crepe twisting the thread of filaments in asingle stage and steaming the thread during the actual insertion of thecrepe twist.

5. Process for the production of highly twisted crepe thread containingfilaments of cellulose acetate which comprises incorporating aplasticizer with the thread containing filaments of cellulose acetate,crepe twisting said thread and, during the actual insertion of the crepetwist, steaming the thread under such conditions that moisture ispresent. v

6. Process for the production of highly twisted crepe thread offilaments of cellulose acetate which comprises incorporating aplasticizer with a thread of filaments of cellulose acetate, crepetwisting said thread in a, single stage and, during the actual insertionof the crepe twist, steaming thread under such contions that moisture ispresent and stretching the filaments of the thread from 5 to 25% oftheir original length.

7. Process for the production of highly twisted crepe thread offilaments of cellulose acetate which comprises incorporating aplasticizer with a thread of filaments of cellulose acetate, crepetwisting said thread and, during the actual insertion of the crepetwist, steaming the thread and stretching the filaments thereof.

8. Process for the production of highly twisted crepe thread offilaments of cellulose acetate which comprises incorporating a coatingcontaining an aryl phosphate with a thread of filaments of celluloseacetate, crepe twisting said thread and steaming the thread during theactual insertion of the crepe twist.

9. Process for the production of highly twisted crepe thread offilaments containing a cellulose ether, which comprises incorporating aplasticizer ments in a single stage and steaming the thread during theactual insertion of the crepe twist.

10. Process for the production of highly twisted crepe thread offilaments of a cellulose ether, which comprises incorporating aplasticizer with a thread of filaments of a cellulose ether, crepetwisting said thread in a single stage and, during the actual insertionof the crepe twist, steaming the thread under such conditions thatmoisture is present.

11. Process for the production of highly twisted crepe thread offilaments, containing cellulose acetate, which comprises incorporatinga. plasticizer with the thread, steaming the thread, and

crepe twisting the thread while it is subjected to the action of steam.I

CAMILLE DREYFUS.

